The Microbial Geography of the operating room

Recent works have shown that C-section Operating Rooms (OR) are not necessarily spotlessly clean and germ-free. Previous work has shown that the surfaces from walls and the dust in these spaces containin human related microbiota. The distribution of this microbial diversity in ORs and its associations with physical and environmental parameters of the OR surfaces, remains to be established. We hypothesize that the structure of the OR microbiota will vary depending on the location of the area sampled on the walls' surface. To test this hypothesis, we determined the structure of bacterial diversity in intensively sampled wall surfaces of an OR after a C-section procedure. Samples were taken from wall-adjacent floors and at three vertical distances measured from the floor level (0 cm., 30 cm., 90 cm., and 150 cm) and every 30 cm horizontally for each of the 4 walls (n= 260 samples). Total DNA was isolated, and the V4 region of 16S rRNA gene was amplified using barcoded universal prokaryotic primers. The resulting amplicons were sequenced using the Illumina MiSeq platform. Sequences were computationally analyzed using Qiime1 software. Height from the floor structured the bacterial beta diversity in the OR (ANOSIM, p-value <0.05), increased height was associated with decreased alpha diversity (t test, p-value <0.05), and increased bacterial community's Unifrac distances. The main taxa reducing its relative abundance with height were members of Proteobacteria, Crenarchaeota and Euryarchaeota. This study reveal that OR conceals an diverse array of bacteria that are unevenly distributed through the vertical dimension of the built environment. The results point out to potential relevant connections between location of the sample, use of the space, and variations in bacterial composition to which C-section delivered newborns are exposed at birth. The results are relevant to the environmental bacterial exposure and seeding of the 30 - 50% of urban infants are born by C-section.